Scraping-iron for road planing machines



Oct. 9, 1934. G. J.' J. SMlTT SCRAPING IRON FOR ROAD PLANING-MACHINES Filed Sept. 30. 1931 655M Johan Tomb 5 24 v ENTQ evil; Mfomo Patented Oct. 9, 1934 UNITED STATES SCRAPING-IRON FOR ROAD PLANING MACHINES Giista Johan Jakob Smitt, Vasteras, Sweden Application September 30, 1931, Serial No. 566,058 In Sweden June 12, 1931 1 Claim.

It is true that scraping-irons for road planing machines wear very irregularly, the mid portion of the iron being affected by wear to a considerably greater extent than at its ends. This irregular wear and tear are the result of the road surface being generally more or less crowned, which brings about excessive wear at the mid portion of the iron.

The object of this invention is to overcome this drawback and consists therein that the iron, comprising a lengthened plate composed of a plurality of pieces if desired, and symmetric around its longitudinal axis, is shaped in such a manner that a regular and uniform wear and tear takes place when the same is used on a crowned road surface.

For this purpose the iron may for instance be shaped in such a manner that the thickness of the iron increases towards the middle from the edges running parallel to the longitudinal axis of the iron. By shaping the iron in this way the advantage is obtained that, as the iron is worn at the middle part owing to its planing the crowned road surface, the resistance to wear and tear at this place is increased on account of the further increased cross section, by which irregularity in wearing is counteracted.

According to one modification the thickness of the iron may taper off from the mid portion thereof towards the opposite ends.

The wear material of the iron may be increased also in another way, viz by shaping the iron as a notching-iron, in which the width of the teeth increases towards the middle line. Hereby the interspaces between the teeth may be kept constant or vary. The interspaces may also be adapted to contain the common bolts for fastening the iron, by which the strength of the iron is not weakened by bolt holes and by which the resistance against wear is further increased.

Some embodiments of the invention are illustrated in the accompanying drawing.

Fig. 1 shows a vertical cross section of the invention of an embodiment applied to an iron corrugated in its whole extension whereas Fig. 1 is a substantially transverse sectional view taken on lines 1 -1 of Figure 1.

Figures 2 and 3 show sections similar to that of Figure 1 except that scraping-irons are of the smooth surface type.

Figure 4 shows a substantially longitudinal section of a smooth scraping-iron illustrating the invention applied in another way.

Figure 5 is a plan view of the left half of an iron, according to a further embodiment of the invention, whereas Figure 6 shows a cross section of the same iron.

1 indicates the scraping-iron and 2 the mold board for fastening the iron to the road planing machine.

According to the embodiment shown in Figure 1 the iron 1 is corrugated along its entire cross direction, the cross section of the iron increasing towards the middle seen from the edges. Double rows of holes 3 may be at hand for fastening the iron, the holes being thereby preferably arranged zigzag.

According to Figures 2-4. the iron is smooth, consequently without any corrugations, but increasing towards the middle counted from the edges in the same manner as in Figure 1. In cross section the iron may be flat on one side and convex on the other side having one or two rows of holes. The iron may also be convex on both sides.

In Figure 4 is illustrated a modification, according to which the thickness of th iron, being smooth also in this case, increases from the ends towards the middle.

In Figure 5 the iron 1 has been provided with recesses 4 running from both the edges. A row of teeth 5 is thus formed on both sides of the iron. As is clear from Figure 5 the width of the teeth increases towards the centre line 6 of the iron, by which the teeth may each have a somewhat increased width or be divided into groups, of mutually the same width in every group. The recesses or the interspaces 4 may be of a constant width or may also vary. If the width of the recesses decreases towards the centre line of the iron the teeth may have constant width.

In some of the interspaces there may also be located bolts serving for fastening the iron to the board as mentioned above.

It may be observed that in the present construction of the road-iron as a comparably thin plate the great advantage is obtained that so to say the road material .may flow over the upper edge of the iron without hindering the work.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

A scraping iron for a grading machine, comprising a corrugated rectangular blade having the corrugations thereof disposed transversely of the longitudinal axis of the blade and being tapered off from its mid portion towards the longitudinal sides of the blades.

GSTA JOHAN JAKOB SMITT. 

